The intensity of the intervalence band in a mixed valence molecule provides a measure of the extent of electron delocalization between the centers involved in the charge transfer act. Molecules will be prepared containing both Ru(II) and Ru(III) at known relative locations, and the intervalence absorption will be studied as a function of the intervening matter. The approach provides a convenient way to obtain information important to understanding electron transfer, including electron transfer in systems of biological interest. Research will be continued on selective attachment of heavy metal atoms to polar groups which appear in polypeptides, proteins, polynucleotides. Current work with ruthenium ammines will be continued but the scope of the effect will be broadened to include kinetically stable attachment of osmium moieties, and to a dirhodium(III) species. The latter is expected to have an especially high affinity for chelating groups which form 4-membered rings. The third area of interest is the modification of the reactivity of ligands by coordination to metals. The effect of ruthenium in each of the oxidation states of 2 ion, 3 ion, and 4 ion is to be studied and the reaction types include the addition of CO to amines to form amino acis, and alkyl transfer from sulfur to other nucleophiles.